Article · Titanium · Hardened Steel
Advanced Tool Paths Improve Cutter Performance in Difficult Materials
Trochoidal tool paths control heat by controlling the arc of engagement — letting you run difficult alloys faster, deeper, and with longer tool life. Here's how to set them up.
Originally published in MoldMaking Technology, by Mike MacArthur, 2009
Difficult materials fail tools through heat. Trochoidal tool paths — curved, rolling cuts instead of straight gouges — lower and stabilize the arc of engagement, so the edge spends less of each revolution buried in the cut. Less engagement means less heat, and controlled heat is what lets you push surface speed in alloys that normally punish it.
The setup that works
- Use a tool sized 50 to 62 percent of the slot width.
- Radial step-over of 2 to 10 percent of the cutter diameter — smaller for the toughest alloys.
- Axial depth of cut up to two times the cutter diameter.
- Pick a tool designed for both trochoidal cutting and the specific material — geometry matters as much as the path.
- Use hybrid paths: trochoidal-type motion in corners and tight areas to keep tool pressure constant.
What it delivers — real test cases
The same approach scales across materials. In Ti-6Al-4V, a 1/2" 6-flute cutter at 400 SFM and 75 IPM with a 0.050" radial width and 1" axial depth cleared the test in 15 minutes. In aluminum, a 1/2" 3-flute tool at 14,000 RPM and 336 IPM finished in 1 minute 30 seconds. In hardened steel, a 3/8" 6-flute cutter ran 125 IPM. The constant across all three: tool pressure that doesn't fluctuate.
Control the arc of engagement and you control heat — which is how difficult materials get cut fast without trading away tool life.
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